OneSteel says no deadline has been set regarding the future of its Whyalla steelworks in South Australia.

A media report quoted OneSteel as saying its steel manufacturing operation had been given a year to reverse its fortunes or face closure.

But managing director Geoff Plummer says there has been no ultimatum.

He says the company is committed to lifting the return of its steel business in the short-term after it recorded an underlying loss of $185 million last financial year.

"[We are] looking at all of our products and facilities to address the very poor results we had last year," he said.

"There will be changes made at Whyalla over the coming period just as there will be changes made at many of our steel operations over the coming period but it wasn't correct to say that I'd given a deadline for a closure decision."

SA Manufacturing Minister Tom Koutsantonis says the large royalty discounts the company gets on its ore would "evaporate overnight" if the plant were to close.

"They have a massive competitive advantage over their competitors in Australia because their iron ore is so much cheaper and we give them that for the long term viability of Whyalla," he said.